U.S. Pat. No. 4,586,875, which is assigned to the same assignee as the present application, discloses a refrigerant compressor having an oil pump for lubricating the compressor. In addition to the pressure regulator disposed in a pressure regulator bore of the compressor/pump housing, although not shown in the '875 patent, a separate external pressure switch is also required, which is connected to be responsive to the pressure being provided by the oil pump. The pressure switch operates when the oil pressure drops below a predetermined minimum value. Since the compressor crank case is sealed to the associated closed refrigeration system, the crank case pressure varies both above and below atmospheric pressure. Thus, a pressure switch requires a balance line connected to communicate compressor crank case pressure to the switch, for proper operation of the switch, and also for returning oil which leaks through the switch back to the compressor crank case. The pressure switch adds additional cost to the refrigerant compressor, and the balance line provides the opportunity for external oil leaks.